(c) 0.6
Explanation:
Let E be the event of winning a game.
Then, ( not E) is the event of not winning the game or of losing the game.
Then, P(E) = 0.4
Now, P(E) + P(not E) = 1
⇒ 0.4 + P(not E) = 1
⇒ P(not E) = 1− 0.4 = 0.6
∴ P(losing the game) = P(not E) = 0.6